Optimize Substring and StringBuilder usage

Emby.Dlna/DlnaManager.cs

@@ -122,15 +122,15 @@ namespace Emby.Dlna
             var builder = new StringBuilder();
 
             builder.AppendLine("No matching device profile found. The default will need to be used.");
-            builder.AppendLine(string.Format("DeviceDescription:{0}", profile.DeviceDescription ?? string.Empty));
-            builder.AppendLine(string.Format("FriendlyName:{0}", profile.FriendlyName ?? string.Empty));
-            builder.AppendLine(string.Format("Manufacturer:{0}", profile.Manufacturer ?? string.Empty));
-            builder.AppendLine(string.Format("ManufacturerUrl:{0}", profile.ManufacturerUrl ?? string.Empty));
-            builder.AppendLine(string.Format("ModelDescription:{0}", profile.ModelDescription ?? string.Empty));
-            builder.AppendLine(string.Format("ModelName:{0}", profile.ModelName ?? string.Empty));
-            builder.AppendLine(string.Format("ModelNumber:{0}", profile.ModelNumber ?? string.Empty));
-            builder.AppendLine(string.Format("ModelUrl:{0}", profile.ModelUrl ?? string.Empty));
-            builder.AppendLine(string.Format("SerialNumber:{0}", profile.SerialNumber ?? string.Empty));
+            builder.AppendFormat(CultureInfo.InvariantCulture, "DeviceDescription:{0}", profile.DeviceDescription ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "FriendlyName:{0}", profile.FriendlyName ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "Manufacturer:{0}", profile.Manufacturer ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "ManufacturerUrl:{0}", profile.ManufacturerUrl ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "ModelDescription:{0}", profile.ModelDescription ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "ModelName:{0}", profile.ModelName ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "ModelNumber:{0}", profile.ModelNumber ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "ModelUrl:{0}", profile.ModelUrl ?? string.Empty).AppendLine();
+            builder.AppendFormat(CultureInfo.InvariantCulture, "SerialNumber:{0}", profile.SerialNumber ?? string.Empty).AppendLine();
 
             _logger.LogInformation(builder.ToString());
         }

MediaBrowser.Api/Playback/Hls/BaseHlsService.cs

@@ -194,7 +194,8 @@ namespace MediaBrowser.Api.Playback.Hls
             var paddedBitrate = Convert.ToInt32(bitrate * 1.15);
 
             // Main stream
-            builder.AppendLine("#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=" + paddedBitrate.ToString(CultureInfo.InvariantCulture));
+            builder.Append("#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=")
+                .AppendLine(paddedBitrate.ToString(CultureInfo.InvariantCulture));
             var playlistUrl = "hls/" + Path.GetFileName(firstPlaylist).Replace(".m3u8", "/stream.m3u8");
             builder.AppendLine(playlistUrl);
 

MediaBrowser.Api/Playback/Hls/DynamicHlsService.cs

@@ -968,7 +968,8 @@ namespace MediaBrowser.Api.Playback.Hls
             builder.AppendLine("#EXTM3U");
             builder.AppendLine("#EXT-X-PLAYLIST-TYPE:VOD");
             builder.AppendLine("#EXT-X-VERSION:3");
-            builder.AppendLine("#EXT-X-TARGETDURATION:" + Math.Ceiling(segmentLengths.Length > 0 ? segmentLengths.Max() : state.SegmentLength).ToString(CultureInfo.InvariantCulture));
+            builder.Append("#EXT-X-TARGETDURATION:")
+                .AppendLine(Math.Ceiling(segmentLengths.Length > 0 ? segmentLengths.Max() : state.SegmentLength).ToString(CultureInfo.InvariantCulture));
             builder.AppendLine("#EXT-X-MEDIA-SEQUENCE:0");
 
             var queryStringIndex = Request.RawUrl.IndexOf('?');
@@ -983,14 +984,17 @@ namespace MediaBrowser.Api.Playback.Hls
 
             foreach (var length in segmentLengths)
             {
-                builder.AppendLine("#EXTINF:" + length.ToString("0.0000", CultureInfo.InvariantCulture) + ", nodesc");
-
-                builder.AppendLine(string.Format("hls1/{0}/{1}{2}{3}",
+                builder.Append("#EXTINF:")
+                    .Append(length.ToString("0.0000", CultureInfo.InvariantCulture))
+                    .AppendLine(", nodesc");
 
+                builder.AppendFormat(
+                    CultureInfo.InvariantCulture,
+                    "hls1/{0}/{1}{2}{3}",
                     name,
                     index.ToString(CultureInfo.InvariantCulture),
                     GetSegmentFileExtension(request),
-                    queryString));
+                    queryString).AppendLine();
 
                 index++;
             }

MediaBrowser.Api/Subtitles/SubtitleService.cs

@@ -175,11 +175,12 @@ namespace MediaBrowser.Api.Subtitles
                 throw new ArgumentException("segmentLength was not given, or it was given incorrectly. (It should be bigger than 0)");
             }
 
-            builder.AppendLine("#EXTM3U");
-            builder.AppendLine("#EXT-X-TARGETDURATION:" + request.SegmentLength.ToString(CultureInfo.InvariantCulture));
-            builder.AppendLine("#EXT-X-VERSION:3");
-            builder.AppendLine("#EXT-X-MEDIA-SEQUENCE:0");
-            builder.AppendLine("#EXT-X-PLAYLIST-TYPE:VOD");
+            builder.AppendLine("#EXTM3U")
+                .Append("#EXT-X-TARGETDURATION:")
+                .AppendLine(request.SegmentLength.ToString(CultureInfo.InvariantCulture))
+                .AppendLine("#EXT-X-VERSION:3")
+                .AppendLine("#EXT-X-MEDIA-SEQUENCE:0")
+                .AppendLine("#EXT-X-PLAYLIST-TYPE:VOD");
 
             long positionTicks = 0;
 
@@ -190,7 +191,9 @@ namespace MediaBrowser.Api.Subtitles
                 var remaining = runtime - positionTicks;
                 var lengthTicks = Math.Min(remaining, segmentLengthTicks);
 
-                builder.AppendLine("#EXTINF:" + TimeSpan.FromTicks(lengthTicks).TotalSeconds.ToString(CultureInfo.InvariantCulture) + ",");
+                builder.Append("#EXTINF:")
+                    .Append(TimeSpan.FromTicks(lengthTicks).TotalSeconds.ToString(CultureInfo.InvariantCulture))
+                    .AppendLine(",");
 
                 var endPositionTicks = Math.Min(runtime, positionTicks + segmentLengthTicks);
 

MediaBrowser.MediaEncoding/Probing/ProbeResultNormalizer.cs

@@ -1367,7 +1367,9 @@ namespace MediaBrowser.MediaEncoding.Probing
             // OR -> COMMENT. SUBTITLE: DESCRIPTION
             // e.g. -> 4/13. The Doctor's Wife: Science fiction drama. When he follows a Time Lord distress signal, the Doctor puts Amy, Rory and his beloved TARDIS in grave danger. Also in HD. [AD,S]
             // e.g. -> CBeebies Bedtime Hour. The Mystery: Animated adventures of two friends who live on an island in the middle of the big city. Some of Abney and Teal's favourite objects are missing. [S]
-            if (string.IsNullOrWhiteSpace(subTitle) && !string.IsNullOrWhiteSpace(description) && description.Substring(0, Math.Min(description.Length, MaxSubtitleDescriptionExtractionLength)).Contains(":")) // Check within the Subtitle size limit, otherwise from description it can get too long creating an invalid filename
+            if (string.IsNullOrWhiteSpace(subTitle)
+                && !string.IsNullOrWhiteSpace(description)
+                && description.AsSpan().Slice(0, Math.Min(description.Length, MaxSubtitleDescriptionExtractionLength)).IndexOf(':') != -1) // Check within the Subtitle size limit, otherwise from description it can get too long creating an invalid filename
             {
                 string[] parts = description.Split(':');
                 if (parts.Length > 0)
@@ -1375,7 +1377,7 @@ namespace MediaBrowser.MediaEncoding.Probing
                     string subtitle = parts[0];
                     try
                     {
-                        if (subtitle.Contains("/")) // It contains a episode number and season number
+                        if (subtitle.Contains('/', StringComparison.Ordinal)) // It contains a episode number and season number
                         {
                             string[] numbers = subtitle.Split(' ');
                             video.IndexNumber = int.Parse(numbers[0].Replace(".", "").Split('/')[0]);
@@ -1390,8 +1392,11 @@ namespace MediaBrowser.MediaEncoding.Probing
                     }
                     catch // Default parsing
                     {
-                        if (subtitle.Contains(".")) // skip the comment, keep the subtitle
+                        if (subtitle.Contains('.', StringComparison.Ordinal))
+                        {
+                            // skip the comment, keep the subtitle
                             description = string.Join(".", subtitle.Split('.'), 1, subtitle.Split('.').Length - 1).Trim(); // skip the first
+                        }
                         else
                         {
                             description = subtitle.Trim(); // Clean up whitespaces and save it

MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs

@@ -731,19 +731,19 @@ namespace MediaBrowser.MediaEncoding.Subtitles
 
                 var date = _fileSystem.GetLastWriteTimeUtc(mediaPath);
 
-                var filename = (mediaPath + "_" + subtitleStreamIndex.ToString(CultureInfo.InvariantCulture) + "_" + date.Ticks.ToString(CultureInfo.InvariantCulture) + ticksParam).GetMD5() + outputSubtitleExtension;
+                ReadOnlySpan<char> filename = (mediaPath + "_" + subtitleStreamIndex.ToString(CultureInfo.InvariantCulture) + "_" + date.Ticks.ToString(CultureInfo.InvariantCulture) + ticksParam).GetMD5() + outputSubtitleExtension;
 
-                var prefix = filename.Substring(0, 1);
+                var prefix = filename.Slice(0, 1);
 
-                return Path.Combine(SubtitleCachePath, prefix, filename);
+                return Path.Join(SubtitleCachePath, prefix, filename);
             }
             else
             {
-                var filename = (mediaPath + "_" + subtitleStreamIndex.ToString(CultureInfo.InvariantCulture)).GetMD5() + outputSubtitleExtension;
+                ReadOnlySpan<char> filename = (mediaPath + "_" + subtitleStreamIndex.ToString(CultureInfo.InvariantCulture)).GetMD5() + outputSubtitleExtension;
 
-                var prefix = filename.Substring(0, 1);
+                var prefix = filename.Slice(0, 1);
 
-                return Path.Combine(SubtitleCachePath, prefix, filename);
+                return Path.Join(SubtitleCachePath, prefix, filename);
             }
         }
 

MediaBrowser.Providers/MediaInfo/AudioImageProvider.cs

@@ -93,7 +93,7 @@ namespace MediaBrowser.Providers.MediaInfo
 
         private string GetAudioImagePath(Audio item)
         {
-            string filename = null;
+            string filename;
 
             if (item.GetType() == typeof(Audio))
             {
@@ -116,9 +116,9 @@ namespace MediaBrowser.Providers.MediaInfo
                 filename = item.Id.ToString("N", CultureInfo.InvariantCulture) + ".jpg";
             }
 
-            var prefix = filename.Substring(0, 1);
+            var prefix = filename.AsSpan().Slice(0, 1);
 
-            return Path.Combine(AudioImagesPath, prefix, filename);
+            return Path.Join(AudioImagesPath, prefix, filename);
         }
 
         public string AudioImagesPath => Path.Combine(_config.ApplicationPaths.CachePath, "extracted-audio-images");

MediaBrowser.Providers/Plugins/Omdb/OmdbItemProvider.cs

@@ -170,7 +170,7 @@ namespace MediaBrowser.Providers.Plugins.Omdb
                         item.SetProviderId(MetadataProvider.Imdb, result.imdbID);
 
                         if (result.Year.Length > 0
-                            && int.TryParse(result.Year.Substring(0, Math.Min(result.Year.Length, 4)), NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsedYear))
+                            && int.TryParse(result.Year.AsSpan().Slice(0, Math.Min(result.Year.Length, 4)), NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsedYear))
                         {
                             item.ProductionYear = parsedYear;
                         }

MediaBrowser.Providers/Plugins/Omdb/OmdbProvider.cs

@@ -62,7 +62,7 @@ namespace MediaBrowser.Providers.Plugins.Omdb
             }
 
             if (!string.IsNullOrEmpty(result.Year) && result.Year.Length >= 4
-                && int.TryParse(result.Year.Substring(0, 4), NumberStyles.Number, _usCulture, out var year)
+                && int.TryParse(result.Year.AsSpan().Slice(0, 4), NumberStyles.Number, _usCulture, out var year)
                 && year >= 0)
             {
                 item.ProductionYear = year;
@@ -163,7 +163,7 @@ namespace MediaBrowser.Providers.Plugins.Omdb
             }
 
             if (!string.IsNullOrEmpty(result.Year) && result.Year.Length >= 4
-                && int.TryParse(result.Year.Substring(0, 4), NumberStyles.Number, _usCulture, out var year)
+                && int.TryParse(result.Year.AsSpan().Slice(0, 4), NumberStyles.Number, _usCulture, out var year)
                 && year >= 0)
             {
                 item.ProductionYear = year;

MediaBrowser.Providers/Plugins/TheTvdb/TvdbEpisodeProvider.cs

@@ -188,7 +188,7 @@ namespace MediaBrowser.Providers.Plugins.TheTvdb
             for (var i = 0; i < episode.GuestStars.Length; ++i)
             {
                 var currentActor = episode.GuestStars[i];
-                var roleStartIndex = currentActor.IndexOf('(');
+                var roleStartIndex = currentActor.IndexOf('(', StringComparison.Ordinal);
 
                 if (roleStartIndex == -1)
                 {
@@ -207,7 +207,7 @@ namespace MediaBrowser.Providers.Plugins.TheTvdb
                 for (var j = i + 1; j < episode.GuestStars.Length; ++j)
                 {
                     var currentRole = episode.GuestStars[j];
-                    var roleEndIndex = currentRole.IndexOf(')');
+                    var roleEndIndex = currentRole.IndexOf(')', StringComparison.Ordinal);
 
                     if (roleEndIndex == -1)
                     {

MediaBrowser.Providers/Plugins/Tmdb/People/TmdbPersonProvider.cs

@@ -251,9 +251,9 @@ namespace MediaBrowser.Providers.Plugins.Tmdb.People
 
         private static string GetPersonDataPath(IApplicationPaths appPaths, string tmdbId)
         {
-            var letter = tmdbId.GetMD5().ToString().Substring(0, 1);
+            var letter = tmdbId.GetMD5().ToString().AsSpan().Slice(0, 1);
 
-            return Path.Combine(GetPersonsDataPath(appPaths), letter, tmdbId);
+            return Path.Join(GetPersonsDataPath(appPaths), letter, tmdbId);
         }
 
         internal static string GetPersonDataFilePath(IApplicationPaths appPaths, string tmdbId)

MediaBrowser.XbmcMetadata/Parsers/BaseNfoParser.cs

@@ -222,8 +222,16 @@ namespace MediaBrowser.XbmcMetadata.Parsers
 
             if (index != -1)
             {
-                var tmdbId = xml.Substring(index + srch.Length).TrimEnd('/').Split('-')[0];
-                if (!string.IsNullOrWhiteSpace(tmdbId) && int.TryParse(tmdbId, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
+                var tmdbId = xml.AsSpan().Slice(index + srch.Length).TrimEnd('/');
+                index = tmdbId.IndexOf('-');
+                if (index != -1)
+                {
+                    tmdbId = tmdbId.Slice(0, index);
+                }
+
+                if (!tmdbId.IsEmpty
+                    && !tmdbId.IsWhiteSpace()
+                    && int.TryParse(tmdbId, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
                 {
                     item.SetProviderId(MetadataProvider.Tmdb, value.ToString(UsCulture));
                 }
@@ -237,8 +245,10 @@ namespace MediaBrowser.XbmcMetadata.Parsers
 
                 if (index != -1)
                 {
-                    var tvdbId = xml.Substring(index + srch.Length).TrimEnd('/');
-                    if (!string.IsNullOrWhiteSpace(tvdbId) && int.TryParse(tvdbId, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
+                    var tvdbId = xml.AsSpan().Slice(index + srch.Length).TrimEnd('/');
+                    if (!tvdbId.IsEmpty
+                        && !tvdbId.IsWhiteSpace()
+                        && int.TryParse(tvdbId, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
                     {
                         item.SetProviderId(MetadataProvider.Tvdb, value.ToString(UsCulture));
                     }
@@ -442,8 +452,8 @@ namespace MediaBrowser.XbmcMetadata.Parsers
                     {
                         var val = reader.ReadElementContentAsString();
 
-                        var hasAspectRatio = item as IHasAspectRatio;
-                        if (!string.IsNullOrWhiteSpace(val) && hasAspectRatio != null)
+                        if (!string.IsNullOrWhiteSpace(val)
+                            && item is IHasAspectRatio hasAspectRatio)
                         {
                             hasAspectRatio.AspectRatio = val;
                         }